High iodine adsorption by lignin-based hierarchically porous flower-like carbon nanosheets

Developing an efficient adsorbent for adsorbing and capture radioactive iodine as a fission product in air and aqueous solution during the nuclear disposal process and in the event of a nuclear accident is of great importance. In this work, lignin-based porous flower-like carbon nanosheets have been developed by using lignin as a carbon precursor, MgO as a template coupled with KOH-activation (LFC-K), and KOH/NaOH eutectic activation (LFC-KN), which were tested for the adsorption of iodine molecules in iodine vapor and in solution. The combination of nanosheets structure and abundant pores makes LFC-K, and LFC-KN excellent absorbability for iodine. The LFC-K with both micropores and mesopores had a higher adsorption capacity for I2 vapor (4060 mg g−1); in comparison, LFC-KN with both micropores, mesopores and macropores had a higher adsorption capacity for I2 in water (1295 mg g−1). After several iodine adsorption and release cycles, the two adsorbents still exhibit excellent reusability.